1. Technical Field
The disclosure relates generally to integrated circuit (IC) chip modeling, and more particularly, to a method and system for preserving measured temperature and geometric behavior of a hardware model while adjusting the model to match specified target values.
2. Background Art
This invention relates to the field of compact modeling of semiconductor devices and to the problem of making a model “match” both a specific measured set of hardware and a set of nominal geometric and electrical specifications. As shown in FIG. 1A, a model 10 is first fit to a particular sample of hardware and then adjusted to match “nominal values” specified for the device, i.e., design manual targets, to obtain a target model 12. The hardware, including many geometries, is typically measured at two or three temperatures (shown by +marks in FIG. 1A) and the model 10 is fit to match the hardware at all measured geometries and temperatures. This process captures a great amount of physical information about the device. However, design manual targets (shown as * in FIG. 1A) are typically only specified at one (room) temperature where in-line data is taken for line control and only for selected bias conditions at selected geometries. When the model is adjusted to match the design manual targets (model 12), the physical content (correct temperature and geometric behavior) may not be preserved. This is illustrated by how model 12 does not track with model 10.